<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Css 方法判断</title>
</head>
<body>
	<h1>Css 方法判断</h1>
	当前浏览器是否支持 CSS 变量:
	<small id="warn"></small>
	<br>

	<script>
		let isSupported = window.CSS && window.CSS.supports && window.CSS.supports('--test', 0);
	
		warn.innerText = isSupported
	</script>
</body>
</html>